1. Field of the Invention
The present invention relates to an Internet protocol (IP), and more particularly, to an IP packet version converting apparatus and method.
2. Description of the Related Art
An IPv4 packet can be converted into an IPv6 packet and vice versa by using a stateless IP/ICMP translator, which is defined in Request for Comments (RFC) 2765. For example, in the process of converting an IPv4 packet into an IPv6 packet or vice versa, only functions specified in both a header of the IPv4 packet and a header of the IPv6 packet are compatible between the IPv4 packet and the IPv6 packet, while functions specified only in one of the header of the IPv4 packet and the header of the IPv6 packet are not compatible and are thus ignored.
A fragment function of the IPv4 packet can be successfully handed over to the IPv6 packet and a fragment function of the IPv6 packet can be handed over to the IPv4 packet using an expansion header of the IPv6 packet. In short, functions defined in the RFC 2765 are normally transferred between the IPv4 packet and the IPv6 packet. However, functions not specified in the RFC 2765 are ignored in the process of converting the IPv4 packet into the IPv6 packet or vice versa, which results in problems in the converting process. More specifically, there is a great possibility of undesirably losing values recorded in a specific field of the header of the IPv4 packet, a specific field of the header of the IPv6 packet, or the expansion header of the IPv6 packet in the process of converting the IPv4 packet into the IPv6 packet or vice versa. Thus, if those values are accidentally lost, corresponding functions may not be transferred between the IPv4 packet and the IPv6 packet.
For example, an IPv4 security function defined in RFC 3514 is specified in a fragment offset field of the header of the IPv4 packet. Since the IPv4 security function is likely to be ignored in the process of converting the IPv4 packet into an IPv6 packet, it may not be transferred to the IPv6 packet. Accordingly, the IPv6 packet without the IPv4 security function is likely to be vulnerable to hacking attacks.